Guide

Grease interceptor cleaning: a different tank, a different service

Updated

Searches mix these up constantly: a grease interceptor serves a kitchen, an oil interceptor serves a forecourt or car park. They are different tanks with different waste streams, and quoting one when you need the other wastes everyone's time.

The two tanks, plainly

Oil interceptor / separator
Sits on surface water drainage from forecourts, car parks, depots and yards; captures oil and silt so they never reach a watercourse. The waste is hazardous, needing a licensed carrier and consignment note. This site's cost figures (£300–£800 per visit, typical 2026 quotes) are for these.
Grease interceptor / grease trap
Sits on the foul drainage from commercial kitchens; captures fats, oils and grease (FOG) before they solidify in the sewer. Serviced by food-waste and drainage contractors, usually on a frequent cycle because kitchens generate FOG daily.

Why the distinction matters when buying

  • Different contractors: forecourt tanker firms and kitchen grease trap services are often different businesses with different equipment.
  • Different frequency: kitchen traps typically need far more frequent servicing than an annual oil separator schedule, sized to the kitchen's output.
  • Different paperwork: oily separator waste is hazardous waste with consignment notes (see regulations); kitchen FOG waste is handled under general waste duty-of-care rules, still with a licensed carrier.
  • Same principle: in both cases the cheap quote that says nothing about where the waste goes is the one to question.

If your "interceptor" serves a kitchen, ask contractors specifically for grease trap servicing and expect them to price on trap size and kitchen throughput; we do not quote a typical figure for kitchen grease trap visits here because the service cycle varies too much to give one honestly. If it serves a forecourt, car park or yard, our quote form is the right door.

Questions, answered directly

Is a grease interceptor the same as an oil interceptor?

No. A grease interceptor (grease trap) serves a commercial kitchen's foul drainage and captures fats, oils and grease. An oil interceptor (separator) serves surface water drainage on forecourts, car parks and yards and captures fuel, oil and silt. Different tanks, different contractors, different servicing cycles.

How often should a kitchen grease trap be cleaned?

Far more often than an oil separator: frequency follows the trap's size and the kitchen's output, and busy kitchens commonly service monthly or more. There is no single statutory interval; the trap failing (blocked drains, odour, sewer FOG) is the expensive way to discover the cycle was too long.

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